TAIPEI (AFP) - A senior ruling party politician offered concessions on Sunday to demands made by student protesters who have occupied Taiwan's parliament for almost three weeks, urging them to end their occupation.

The Sunflower protest movement took over the chamber on March 18 in protest over a controversial trade pact between Taiwan and China, which has sparked huge rallies in the capital Taipei.

The speaker of parliament, Wang Jin-pyng, entered the chamber surrounded by dozens of legislators from both ruling and opposition parties, security officials and reporters, shaking hands with students, but did not speak directly with protest leaders.

Before the meeting, he said that he would not field any more debate in parliament over the trade pact before a law had been brought in to monitor agreements with China - which is one of the protesters' key demands.

"I hereby guarantee not to mediate any negotiations between the ruling and opposition parties for a legislative session to debate the service trade agreement, before a law (to monitor all agreements with China) is introduced," Mr Wang said, reading from a statement.

Mr Wang, a senior politician from the ruling Kuomintang party, called on the students to give the main chamber back to legislators.

"You've occupied parliament for a long time - as the move has affected the operation of the country and people's welfare, this is not acceptable to our countrypeople," Mr Wang said.

"I urge you to go forward with your ideals, return to your postings ... exercise your strength of tenderness, reasoning and peace, so that the world would be able to respect the width and depth of our democracy."

Acknowledging the "good will" of Mr Wang's move, student leader Lin Fei-fan said the protest group would discuss Mr Wang's appeal for a retreat from the chamber.

Politicians from both ruling and opposition parties have been meeting with the students since the occupation, but it is the first time that the speaker has entered the chamber since it was seized.

Around 200 student-led demonstrators occupied the parliament chamber 20 days ago - the first such seizure in Taiwan's history - swiftly drawing a large crowd of supporters, with more than 10,000 congregated outside the building at one point.

There were violent clashes on March 23 when baton-wielding police turned water cannon on protesters who had stormed the nearby government headquarters.

And on March 30 tens of thousands of protesters gathered to pressure embattled President Ma Ying-jeou to retract the trade pact, which they say will damage Taiwan's economy and leave it vulnerable to political pressure from China.

Mr Ma, who has sought closer ties with China since taking power in 2008, has agreed to the students' demand for a law to monitor all pacts with China, but the protesters have rejected the government's bill.

The pact with China is designed to open up further trade in services between China and Taiwan, which split 65 years ago after a civil war.

Mr Ma, whose approval ratings sit around 10 percent, has warned that failure to ratify the pact would be a grave setback to trade-reliant Taiwan's efforts to seek more free trade agreements and avoid isolation as regional economic blocs emerge.

The deal is a follow-up agreement to a sweeping Economic Cooperation Framework Agreement signed in 2010 to reduce trade barriers between China and Taiwan.

Mr Ma has overseen a marked thaw in relations with Beijing since he came to power pledging to strengthen trade and tourism links. He was re-elected in January 2012.

But China still considers Taiwan as part of its territory awaiting reunification - by force if necessary.